cgroup: Replace deprecated CPU-hotplug functions.

The functions get_online_cpus() and put_online_cpus() have been
deprecated during the CPU hotplug rework. They map directly to
cpus_read_lock() and cpus_read_unlock().

Replace deprecated CPU-hotplug functions with the official version.
The behavior remains unchanged.

Cc: Zefan Li <lizefan.x@bytedance.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: cgroups@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Tejun Heo <tj@kernel.org>

kernel/cgroup/cpuset.c

@@ -979,7 +979,7 @@ partition_and_rebuild_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
  * 'cpus' is removed, then call this routine to rebuild the
  * scheduler's dynamic sched domains.
  *
- * Call with cpuset_mutex held.  Takes get_online_cpus().
+ * Call with cpuset_mutex held.  Takes cpus_read_lock().
  */
 static void rebuild_sched_domains_locked(void)
 {
@@ -1040,11 +1040,11 @@ static void rebuild_sched_domains_locked(void)
 
 void rebuild_sched_domains(void)
 {
-	get_online_cpus();
+	cpus_read_lock();
 	percpu_down_write(&cpuset_rwsem);
 	rebuild_sched_domains_locked();
 	percpu_up_write(&cpuset_rwsem);
-	put_online_cpus();
+	cpus_read_unlock();
 }
 
 /**
@@ -2288,7 +2288,7 @@ static int cpuset_write_u64(struct cgroup_subsys_state *css, struct cftype *cft,
 	cpuset_filetype_t type = cft->private;
 	int retval = 0;
 
-	get_online_cpus();
+	cpus_read_lock();
 	percpu_down_write(&cpuset_rwsem);
 	if (!is_cpuset_online(cs)) {
 		retval = -ENODEV;
@@ -2326,7 +2326,7 @@ static int cpuset_write_u64(struct cgroup_subsys_state *css, struct cftype *cft,
 	}
 out_unlock:
 	percpu_up_write(&cpuset_rwsem);
-	put_online_cpus();
+	cpus_read_unlock();
 	return retval;
 }
 
@@ -2337,7 +2337,7 @@ static int cpuset_write_s64(struct cgroup_subsys_state *css, struct cftype *cft,
 	cpuset_filetype_t type = cft->private;
 	int retval = -ENODEV;
 
-	get_online_cpus();
+	cpus_read_lock();
 	percpu_down_write(&cpuset_rwsem);
 	if (!is_cpuset_online(cs))
 		goto out_unlock;
@@ -2352,7 +2352,7 @@ static int cpuset_write_s64(struct cgroup_subsys_state *css, struct cftype *cft,
 	}
 out_unlock:
 	percpu_up_write(&cpuset_rwsem);
-	put_online_cpus();
+	cpus_read_unlock();
 	return retval;
 }
 
@@ -2391,7 +2391,7 @@ static ssize_t cpuset_write_resmask(struct kernfs_open_file *of,
 	kernfs_break_active_protection(of->kn);
 	flush_work(&cpuset_hotplug_work);
 
-	get_online_cpus();
+	cpus_read_lock();
 	percpu_down_write(&cpuset_rwsem);
 	if (!is_cpuset_online(cs))
 		goto out_unlock;
@@ -2417,7 +2417,7 @@ static ssize_t cpuset_write_resmask(struct kernfs_open_file *of,
 	free_cpuset(trialcs);
 out_unlock:
 	percpu_up_write(&cpuset_rwsem);
-	put_online_cpus();
+	cpus_read_unlock();
 	kernfs_unbreak_active_protection(of->kn);
 	css_put(&cs->css);
 	flush_workqueue(cpuset_migrate_mm_wq);
@@ -2548,7 +2548,7 @@ static ssize_t sched_partition_write(struct kernfs_open_file *of, char *buf,
 		return -EINVAL;
 
 	css_get(&cs->css);
-	get_online_cpus();
+	cpus_read_lock();
 	percpu_down_write(&cpuset_rwsem);
 	if (!is_cpuset_online(cs))
 		goto out_unlock;
@@ -2556,7 +2556,7 @@ static ssize_t sched_partition_write(struct kernfs_open_file *of, char *buf,
 	retval = update_prstate(cs, val);
 out_unlock:
 	percpu_up_write(&cpuset_rwsem);
-	put_online_cpus();
+	cpus_read_unlock();
 	css_put(&cs->css);
 	return retval ?: nbytes;
 }
@@ -2762,7 +2762,7 @@ static int cpuset_css_online(struct cgroup_subsys_state *css)
 	if (!parent)
 		return 0;
 
-	get_online_cpus();
+	cpus_read_lock();
 	percpu_down_write(&cpuset_rwsem);
 
 	set_bit(CS_ONLINE, &cs->flags);
@@ -2815,7 +2815,7 @@ static int cpuset_css_online(struct cgroup_subsys_state *css)
 	spin_unlock_irq(&callback_lock);
 out_unlock:
 	percpu_up_write(&cpuset_rwsem);
-	put_online_cpus();
+	cpus_read_unlock();
 	return 0;
 }
 
@@ -2834,7 +2834,7 @@ static void cpuset_css_offline(struct cgroup_subsys_state *css)
 {
 	struct cpuset *cs = css_cs(css);
 
-	get_online_cpus();
+	cpus_read_lock();
 	percpu_down_write(&cpuset_rwsem);
 
 	if (is_partition_root(cs))
@@ -2855,7 +2855,7 @@ static void cpuset_css_offline(struct cgroup_subsys_state *css)
 	clear_bit(CS_ONLINE, &cs->flags);
 
 	percpu_up_write(&cpuset_rwsem);
-	put_online_cpus();
+	cpus_read_unlock();
 }
 
 static void cpuset_css_free(struct cgroup_subsys_state *css)